The present invention relates to a horn speaker system, and more particularly to a horn speaker system having a dome-shaped diaphragm.
Horn speaker systems primarily for reproducing sounds in a high-frequency range have a dome-shaped diaphragm. The sounds produced by the a dome-shaped diaphragm are collected by a phase equalizer and then introduced into a horn, from which the sounds are radiated into an exterior space.
The horn speaker system is unable to achieve designed frequency characteristics unless the magnetic circuit for actuating the diaphragm is positioned accurately with respect to the diaphragm. Therefore, the components of the magnetic circuit, including a magnet, are assembled precisely with jigs. In particular, it has been customary to define a gap in which a voice coil is to be disposed, precisely with a jig called "gap gage" because the width of the gap is very small. However, it has been tedious and time-consuming to produce such a gap precisely with the gap gage.
Some of the components of the magnetic circuit, e.g., the magnet, are difficult to fasten with screws due to their structural limitations. Those components are usually fixed in place by an adhesive. One problem with the use of adhesive is that the adhesive applied to bond the components tends to block the flow of magnetic fluxes in the magnetic circuit, resulting in a reduction in the magnetic efficiency and hence a degradation of the speaker characteristics.
It is important that the diaphragm of a horn speaker system be reduced in weight for improved speaker performance, e.g., the quality of reproduced sounds, the energy conversion efficiency, etc. It is also desired that the horn speaker systems be capable of reproducing sounds with as flat a frequency characteristic curve in a wide frequency range.
One form of diaphragm for use in a horn speaker system is integrally formed with an edge and comprises a metal sheet. In order to maintain a degree of durability and rigidity required by the edge, the thickness of the metal sheet is greater than that of a diaphragm which is separate from an edge. Therefore, the metal sheet is relatively heavy, with the result that the horn speaker system has poor frequency characteristics and response characteristics.
Phase equalizers for use in horn speaker systems can keep accurate phase matching unless properly shaped. In the absence of accurate phase matching, sounds reproduced by the horn speaker system may be unclear or may not have a flat frequency characteristic curve. It has been tedious and time-consuming to design a phase equalizer for desired good frequency characteristics.